Anxiety has been defined as excessive or inappropriate arousal characterized by feelings of apprehension, uncertainty, and fear. Often, there is no real or appropriate threat to which the anxiety can be attributed. Nevertheless, anxiety can paralyze an individual into inaction or withdrawal. Anxiety can also be a symptom of other psychologic or medical problems, such as depression, substance abuse, or thyroid disease.
Anxiety disorders are the most common psychiatric condition in the United States as about 25 million Americans experience anxiety disorders at some time during their lives. In recent years, a number of different anxiety disorders have been classified; the two primary ones are generalized anxiety disorder (GAD), which is long-lasting and low-grade, and panic disorder, which has more dramatic symptoms. Other anxiety disorders include phobias, performance anxiety, obsessive-compulsive disorder (OCD), and post-traumatic stress disorder (PTSD).
Although a number of different treatment protocols have been developed for use in the treatment of anxiety disorders, there is a continued interest in the development of new treatment methodologies and agents for use in treating these conditions.